Lighting systems that are able to generate light having different colors or different color temperatures are known in the art. US20070153514, for instance, describes methods and systems for illuminating environments, including aircraft environments. The methods and systems include facilities for providing both white and non-white illumination, with color and color temperature control, in programmed response to inputs. Methods and systems are also provided for improving the addressing of light systems in a network lighting configuration. This document especially describes a method comprising (a) controlling at least one light via a lighting control signal to provide illumination including at least one of a white color and a non-white color, the at least one light comprising at least one first LED configured to generate first radiation and at least one second LED configured to generate second radiation different from the first radiation, and (b) generating the lighting control signal based at least in part on data provided by the at least one light, wherein the non-white color or a color temperature of the white color is determined by mixing particular amounts of the first radiation and the second radiation in response to the lighting control signal.
WO2009090596 describes a lighting device comprising one or more light sources arranged to generate light, an accommodating device having an external boundary which is at least partly translucent and which is arranged to accommodate the one or more light sources and a controller. The lighting device can generate two types of light. One or more lighting parameters selected from the group consisting of the first luminous intensity of the first type of light, the second luminous intensity of the second type of light, the color point of the first type of light and the color point of the second type of light can be controlled. This allows task lighting and atmosphere lighting. The invention is also directed to a method of providing a wake-up stimulus by means of such a lighting device.
US2009303694 describes a light emitting device comprising a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven. The light emitting device can be diversely applied in a desired atmosphere and use by realizing white light with different light spectrums and color temperatures. Particularly, an effect on health by adjusting the wavelength of light or the color temperature according to the circadian rhythm of humans is assumed.